decl.c (components_to_record): Do not reorder fields in packed record types if...

* gcc-interface/decl.c (components_to_record): Do not reorder fields
	in packed record types if they contain fixed-size fields that cannot
	be laid out in a packed manner.

From-SVN: r276036
This commit is contained in:
Eric Botcazou 2019-09-23 07:45:58 +00:00 committed by Eric Botcazou
parent 2d814ac2f7
commit fdfa0e44b7
2 changed files with 17 additions and 4 deletions

View File

@ -1,3 +1,9 @@
2019-09-23 Eric Botcazou <ebotcazou@adacore.com>
* gcc-interface/decl.c (components_to_record): Do not reorder fields
in packed record types if they contain fixed-size fields that cannot
be laid out in a packed manner.
2019-09-19 Tom Tromey <tromey@adacore.com>
* gcc-interface/misc.c (gnat_get_type_bias): Return the bias

View File

@ -7521,6 +7521,7 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
bool all_rep_and_size = all_rep && TYPE_SIZE (gnu_record_type);
bool variants_have_rep = all_rep;
bool layout_with_rep = false;
bool has_non_packed_fixed_size_field = false;
bool has_self_field = false;
bool has_aliased_after_self_field = false;
Entity_Id gnat_component_decl, gnat_variant_part;
@ -7577,6 +7578,10 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
has_self_field = true;
else if (has_self_field && DECL_ALIASED_P (gnu_field))
has_aliased_after_self_field = true;
else if (!DECL_FIELD_OFFSET (gnu_field)
&& !DECL_PACKED (gnu_field)
&& !field_has_variable_size (gnu_field))
has_non_packed_fixed_size_field = true;
}
}
@ -7868,8 +7873,9 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
self-referential/variable offset or misaligned. Note, in the latter
case, that this can only happen in packed record types so the alignment
is effectively capped to the byte for the whole record. But we don't
do it for non-packed record types if pragma Optimize_Alignment (Space)
is specified because this can prevent alignment gaps from being filled.
do it for packed record types if not all fixed-size fiels can be packed
and for non-packed record types if pragma Optimize_Alignment (Space) is
specified, because this can prevent alignment gaps from being filled.
Optionally, if the layout warning is enabled, keep track of the above 4
different kinds of fields and issue a warning if some of them would be
@ -7880,8 +7886,9 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
const bool do_reorder
= (Convention (gnat_record_type) == Convention_Ada
&& !No_Reordering (gnat_record_type)
&& (!Optimize_Alignment_Space (gnat_record_type)
|| Is_Packed (gnat_record_type))
&& !(Is_Packed (gnat_record_type)
? has_non_packed_fixed_size_field
: Optimize_Alignment_Space (gnat_record_type))
&& !debug__debug_flag_dot_r);
const bool w_reorder
= (Convention (gnat_record_type) == Convention_Ada